Database analysis investigates leaflet thrombosis after TAVI

30 Aug 2017

A new study, based on reports from an adverse events and outcomes database, identified leaflet thrombosis as a possible mechanism of complications following transcatheter aortic valve implantation (TAVI). The insights, presented in a Hot Line: Late-Breaking Registry Results session yesterday reveal that clinically relevant consequences as a result of leaflet thrombosis usually occur in the first year after TAVI.

Topic(s):

Cardiovascular Surgery

Interventional Cardiology and Cardiovascular Surgery

"Leaflet thrombosis is a recently recognised mechanism of transcatheter heart valve failure. Leaflet thrombosis presents as aortic stenosis more frequently than regurgitation,” said Doctor Ankur Kalra (Case Western Reserve University School of Medicine, Cleveland, USA).

The MAUDE (US Manufacturer and User Facility Device Experience) database contains reports of adverse events involving medical devices that are submitted to the Food and Drug Administration (FDA) and can be used to identify under-recognised device-related events.

The investigators searched the database between 2012 and 2015 using the NPT code used to identify TAVI-related adverse events. They refined the search using terms such as leaflet, central aortic regurgitation and aortic stenosis and recorded data on the presentation of leaflet thrombosis; mode of diagnosis; and timing of onset after TAVI.

Researchers found that there were 5,691 TAVI-related adverse events reported in the MAUDE database. Of these, 546 were separated based on the search terms. There were 156 structural valve dysfunction events included in the final analysis (129 were leaflet restriction and 27 were malcoaptation). The majority (60%) of leaflet thrombosis cases occurred in the first year after TAVI and the others in the period between 13 and 60 months after TAVI.

Commenting on further results from the study, Dr. Kalra said: “Structural valve dysfunction presented as aortic stenosis (53.3%), regurgitation (23.3%) and both (13.3%). The other patients had a stroke/transient ischaemic attack. Interventions to address leaflet thrombosis were mainly antiplatelet or anticoagulant therapy (26.7%); valve-in-valve TAVI (10%); and reoperations (46.7%). Diuretics, thrombus aspiration, balloon aortic valvuloplasty, or no intervention were used in others.

“Early diagnosis of leaflet thrombosis may be crucial for planning appropriate management and optimising clinical outcome for patients,” Dr. Kalra concluded, while acknowledging that the study had several limitations inherent to a self-reported, publically available database.

Chairperson Professor Martin Cowie (Imperial College London, UK) highlighted the importance of establishing the seriousness of the problem and getting a real-world picture for regulators, reimbursement, clinicians and patients.

Commenting on the dataset, Professor Stephan Achenbach (University of Erlangen, Germany) states, “This was a database of patients with clinical problems, and not a database of patients with leaflet thrombosis that was used for this analysis. Hence, one cannot conclude from this data how often leaflet thrombosis results in severe consequences. One would have to put the number of problems reported here—156 cases, out of which about one-half underwent surgery—in relation to the overall number of TAVI procedures performed, likely tens of thousands. While leaflet thrombosis may be the underlying mechanism when bioprosthetic heart valve failure occurs, many imaging trials published in the last year showed that leaflet thrombosis is not infrequent, usually resolves spontaneously or with anticoagulation, and that clinically relevant consequences are seldom seen.”